The Dimasa Kingdom (also Kachari kingdom) was a late medieval/early modern kingdom in Assam, Northeast India ruled by Dimasa kings. The Dimasa kingdom and others (Kamata, Chutiya) that developed in the wake of the Kamarupa kingdom were examples of new states that emerged from indigenous communities in medieval Assam as a result of socio-political transformations in these communities. The British finally annexed the kingdom: the plains in 1832 and the hills in 1834. This kingdom gave its name to undivided Cachar district of colonial Assam. And after independence the undivided Cachar district was split into three districts in Assam: Dima Hasao district (formerly North Cachar Hills), Cachar district, Hailakandi district. The Ahom Buranjis called this kingdom Timisa.
In the 18th century, a divine Hindu origin was constructed for the rulers of the Kachari kingdom and it was named Hidimba, and the kings as Hidimbesvar. The name Hiḍimbā continued to be used in the official records when the East India Company took over the administration of Cachar.
Origins
The origin of the Dimasa Kingdom is not clear. According to tradition, the Dimasa had their domain in Kamarupa and their king belonged to a lineage called Ha-tsung-tsa or Ha-cheng-sa, a name first mentioned in a coin from 1520. Some of them had to leave due to a political turmoil and while crossing the Brahmaputra some of them were swept away—therefore, they are called Dimasa ("Son-of-the-big-river"). The similarity in Dimasa traditions and religious beliefs with those of the Chutiya kingdom supports this tradition of initial unity and then divergence. Linguistic studies too point to a close association between the Dimasa language and the Moran language that was alive till the beginning of the 20th-century, suggesting that the Dimasa kingdom had an eastern Assam presence before the advent of the Ahoms. The eastern Assam origin of the Dimasas is further reinforced by the tradition of the tetulary goddess Kecaikhati whose primary shrine was around Sadiya; the tribal goddess common to many Kachari peoples: as the Rabhas, Morans, Tiwas, Koch, Chutias, etc.
According to legend Hachengsa (or Hasengcha) was an extraordinary boy brought up by a tiger and a tigress in a forest near Dimapur who replaced the existing king following divine oracles; which likely indicates the emergence of a strong military leader able to consolidate power. Subsequently, the Hasengcha Sengfang (clan) emerged and beginning with Khorapha (1520 in Dimapur), the Dimasa kings continued to draw lineage from Hachengcha in Maibong and Khaspur till the 19th century.
Given different traditions and legends, the only reliable sources of the early history of the Dimasa kingdom is that given in the Buranjis, even though they are primarily narrations of wars between the Ahom and the Dimasa polities.
Early history
The historical accounts of the Dimasas begin with mentions in Ahom chronicles: according to an account in a Buranji, the first Ahom king Sukaphaa (r. 1228–1268) encountered a Kachari group in the Tirap region (currently in Arunachal Pradesh), who informed him that they along with their chief had to leave a place called Mohung (salt springs) losing it to the Nagas and that they were settled near the Dikhou river. This supports a tradition that the eastern boundary of the Kachari domain extended up to Mohong or Namdang river (near Joypur, Assam) beyond the river Dichang, before the arrival of Ahoms. Given the settlement was large, Sukaphaa decided not to engage with them before settling with the Barahi and Moran polities. During the reign of Sukaphaa's successor Suteuphaa () the Ahoms negotiated with this group of the Dimasa, who had been in the region between Dikhou and Namdang for about three generations by then, and the Dimasa group moved to the west of the Dikhou river. These isolated early accounts of the Dimasas suggest that they controlled the region between the Dikhu river in the east and the Kolong river in the west and included the Dhansiri valley and the north Cachar hills from the late 13th century.